Sewing machine



Aug. 17, 1948.

Filed May 20, 1946 N. v. CHRISTENSEN 2,447,115

SEWING MACHINE 7 Sheets-Sheet l Ha I "Hum

- IN VEN TOR. NORMAN MCHR/S TEMSEN Aug, 17, 1948. N. v. CHRISTENSEN 2,447,115

SEWING MACHINE Filed May 20, 1946 '7 Shets-Sheet 2 IN VEN TOR.

NORMAN l/CHR/S TEMS'ENI l c I Aug. 1'], 1948. N. v. CHRISTENSEN 2,447,115"

SEWING MACHINE Filed May 20, 1946 7 Sheets-Sheet 3 I 'I/I/l/I 55 50,77

I N V EN TOR. NORMA/V MCHR/STE/VSEN AYY'UE/YE 1948. N. v. CHRISTENSEI; 2,447,115

SEWING MACHINE Filed May 20, 1946 7 Sheets-Sheet 4 0 0 00 0 000 0.00 Q Q 00 0 0 0 00000 000 0 0.200: 00 00'00 00 0 0&0 .0 00 0 A04.

INVENTOR. NORMA/V M CHRISTENSEN 1948. N. v. CHRISTENSEN 2,447,115

SEWING MACHINE Filed May 20, 1946 '7 Sheets-Sheet 5 IN V EN TOR. NORMA/V 1/ CHRISTENSEN Aug. 1948- N. v. CHRISTENSEN 2,447,115

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SEWING MACHINE Filed May 20, 1946 7 Sheets-Sheet 7 MIMI Hi l...

EXIT EHO]? NORM/4N l/ C RISTENSE 5y ATTORZVE Patented Aug. 17, 1948 Norman V. Christensen, Chicago, Ill., assignor to Union Special Machine Company, Chicago, 111., a corporation of Illinois Application May 20, 1946, Serial No. 671,068

7 Claims.

This invention relates to an improved sewin machine construction and more particularly to a power-driven sewing machine having a generally enclosed housing, and having associated therewith means for forcing air through said housing in order to cool, clean and lubricate said machine.

In modern sewing machines, particularly of the industrial type, it is frequently desirable to use high-speed operation. There results, however, a considerable problem in that moving parts within the frame have a tendency to overheat, with resulting deterioration of lubricant and parts of the machine. The stitch-forming elements, particularly needles, also have an undesirable tendency to overheat.

Another serious problem encountered in sewing machines is the accumulation of lint, dust, filler from new cloth, and other foreign matter on the moving parts of the machine, particularly within the frame or housing.

A primary object of the present invention is to aid in the solution of the above problems by fo-ncing air through the interior of the housing in such a manner as to cool and clean same and the parts therein and aid in properly distributing lubricant within the housing.

An important feature of the present invention is that a superatmospheric pressure is maintained within the housing, and as a result, air continually is emitted from various openings therein, thereby ejecting lint and other undesirable material from this region and preventing .the entry of such material.

A further feature of one embodiment of the invention is that the air introduced int'othe frame is drawn from the atmosphere at a point which because of its location is relatively free from suspended lint and other undesirable material, and furthermore, this air is filtered before :being drawn into the system.

A further feature of one embodiment .of the invention is that in combination with the improved means for circulating air through said housing means are provided for directing .a blast of air directly against the needle, thereby cooling same.

Other objects, features and advantages of the invention will appear from the detailed description of an illustrative embodiment of the same which will now be given in conjunction with the accompanying drawings in which:

Fig. 1 is a front elevational view of an :overedger sewing machine on a supporting :table with a blower unit and a lubrication reservoir underneath the table, together with means for conduct- 2 ing air from the blower unit to the machine. In this view the filter screen which normally covers the intake opening of the blower unit vhas been removed.

Fig. 2 is an elevational view of the machine shown in Fig. 1, as seen from the right side.

Fig. 3 is a view chiefly in elevation, and partly in section, of the left side .of the machine and blower unit shown in Fig. 1, together with its associated transmitter unit.

Fig. 4 is an elevational view of the cover plate of the blower unit, bearing the filter screen covering the air intake opening.

Fig. 5 is a sectional view of the unassembled blower cover plate and filter screen.

Fig. 6 is a sectional view :of the components of Fig. 5, assembled.

Fig. '7 is a perspective view of the blower filter, as seen from a point within the blower.

Fig. 8 is a front elevational view of an embodiment of the invention utilizing a separate motor for driving the blower.

Fig. 9 is a side elevational view of the embodiment shown in Fig. 8, as seen from the .left, cer' tain portions being broken away.

Reference is now made to Fig. 1. There is illustrated a sewing table I'll. Supported from this table on shock absorbers ii is a base plate 12. Rising from this base plate is a standard l3 which is provided with various cover plates so as to form an enclosed housing or frame for the machine. This standard carries bearings not shown, and journalled in these bearings is a shaft 14. Mounted "on this shaft is a series of rotary actuators or eccentrics, one of which, I5, is illustrated as a part of the machine in Fig. 1. This eccentric is provided with bores 16 for dynamic balancing. Cooperating with this eccentric is an eccentric strap H to which is attached a connecting or pitman rod I8. Other eccentrics are provided with similar straps and connecting rods. The standard is provided with a forwardly-reaching projection -l 9. This projection carries a bushing, not .shown,.and there is provided a needle bar, 20, shown in Fig. 2, which is confined to substantially vertical reciprocation by this bushing. This needle bar carries at its lower end a needle "21.. Cooperating with this needle are a spreader 22 and a looper 23. Shaft i4 is rotatable and is driven by means to be described at a later point. When this shaft is rotated, it, in cooperation with the various eccentrics, straps, connecting rods, and suitable means, drives the needle 2|, the spreader 22, the looper 23, and various other moving parts of the machine. For more details of 3 such suitable means, reference may be made to Patent 1,864,391 granted to Frederick F. Zeier on June 21, 1932,

The illustrated machine is provided with an air circulation system, to be described at a later point, and with a lubricating system described in detail in pending application Serial No. 641,681 filed J anuary 16, 1946 in the name of George Sauer, inventor. As part of this lubricating system, the machine is provided with an oil drainage surface 24 within the standard, as shown in Fig. 1. Supported beneath table I is an oil reservoir and filter means, indicated generally by the numeral 25. Oil drains from various lubricated parts within the machine and from drainage surface 24 through a tube 26 into the oil reservoir 25. Oil is drawn from this oil reservoir, being filtered in the process, through a tube 21 by an intermittently-acting pump not shown. This pump may be actuated by the operator in connection with some sewing operation.

Reference may now be made to Fig. 2. In this view, the supporting plate, sewing table, and components below same have been omitted, as has the air conduit from the blower, not yet mentioned. Journalled in a cover plate 28 which forms part of the housing is a rock shaft 29. Extending radially from shaft 29 is an arm or lever 30. As shown in Fig. 2, shaft 29 is urged in a counterclockwise direction by a spring means 31, one end of which is attached to cover plate 28 as shown at 32 and the other end of which engages lever 36, being bent around same. Attached to the free end of lever 36 is a chain 33 connected to a treadle not shown. Rock shaft 29 is connected by appropriate means to the previously-mentioned pump, and the operator may, by depressing the treadle mentioned, thus operate the pump. i

' As shown in Fig. 3, the machine is provided with a presser foot 34. Reference isagain made to Fig. 2. Journalled in the standard is a rock shaft 35, This shaft is connected by a series of appropriate linkages to the presser foot so as to control same. This shaft is controlled by a lever or arm 36, rigidly connected to said shaft. Attached to the free end of this lever is a chain 31 connected to a treadle, not shown. The operator may, by depressing this treadle, control the motion of rock shaft 35, which as stated controls the presser foot. The treadles connected to chains 31 and 33 may, if desired, be one and the same, so that in operating the presser foot for each seaming operation, the operator may operate the pump automatically.

Oil leaves the pump through a tube 38 shown in Fig. 1 and Fig. 2, which is connected to the pump through an elbow connection 39, shown in Fig. 1. The machine is provided with a reservoir within the housing in the region 46, and oil passes into this reservoir from tube 38 through an elbow connection 4|. As shown in Fig. 3, a sight gauge 42 for indicating the oil level is fitted into this reservoir, In this figure a portion of the wall of the reservoir has been broken away for clarity of illustration, and the oil within the reservoir may be seen in this region. A portion of the housing has been broken away in another region, and a portion of an eccentric strap and connecting rod may be seen in this region.

As described in detail in application Serial No. 641,681, oil is drawn from the last-mentioned reservoir into a well and is pumped from this well by means of a pump formed as part of shaft [4 and its bearing. This shaft is provided with a longitudinal bore 43 shown in Fig. 1. The various eccentrics are provided with radial ducts, and the connecting rods are tubular in construction. Oil is drawn from the well by the last-mentioned pump and is forced lengthwise down the shaft and radially through the eccentrics in order to lubricate bearing surfaces of the eccentrics and straps. Oil is furthermore conducted from the straps downwardly through the tubular connecting rods to various bearing surfaces at the lower ends of these connecting rods. Excess oil passing down bore 43 is returned directly to the well by means of a tube 44 and a connection 45, as shown in Fig. 2. This connection is provided with a gits oil cup 46, so that oil may be introduced at this point, if desired. For further details of the lubricating system, reference is made to the previously mentioned application Serial No. 641,681 filed January 16, 1946 in the name of George Sauer, inventor,

As shown in Fig. 2, the machine is provided with thread-tensioning means 47 and 48, and threadcarrying means 49 and 56, of the usual type. The machine is also provided with a combination hand and belt wheel 5|, connected to the aforementioned shaft I4, for driving same.

Reference is now made to Fig. 3, in which the hand and belt wheel 51 may again be seen. This wheel may be operated manually, or may be driven by the pulley 53 of an electric transmitter or motor and clutch unit, designated generally by the reference numeral 54, and shown in Fig. 3 beneath the sewing table. This transmitter unit may be of any suitable, known construction, but

- for purposes of illustration the invention has been shown in combination with a transmitter of the type shown and described in pending application Serial No. 442,585 filed May 12, 1942 now Patent 2,418,429 granted April 1, 1947 in the name of George Sauer, inventor. This unit comprises an electric motor 55 secured to one end of a main frame member or housing 56 adjustably carried by the under surface of the table l6 through suitable mounting means 57. The motor has a main shaft 58 on which there is mounted a fly-wheel 59 within the housing 56. This fiy-wheel is provided with a friction surface 60, and within the housing there is provided an axially shiftable clutch member 6| having a conical surface adapted to be engaged with the friction surface on the fly-wheel whenever the sewing machine is to be operated. Within the housing there is also provided a braking surface, not shown, and the clutch member has a face adapted to be engaged by this braking surface whenever the clutch is disengaged.

The shiftable clutc'li member 6| is secured to a shaft 62, which is adapted to be shifted axially, to engage and disengage the clutch, by the operation of a lever 63, This lever is pivoted at 64 upon a lug 65 projecting from an end plate 66 secured to the end of the housing 56 by means to be described. The upper end of the lever 63 is bifurhated and its branches 61 extend upwardly at opposite sides of a collar 68 extending forwardly from the end plate 66 around the shaft 62. Each branch 61 is forked or otherwise formed at its upper end to engage a projection 69 extending radially outward from a sleeve 10 slidable axially Within the collar 68 and suitably connected with the shaft 62 to impart endwise shifting motion to the latter. Projections 69 extend through slightly elongated slots in the collar 68 to permit the operation of the lever 63 and the axial shifting of the shaft 62 in the manner described. The

lever 63 is normally drawn by a spring H into such a position that the clutch is disengaged from the fiy-wheel and is engaged with the braking surface. Operation of the lever 63 in opposition to the spring H may be effected in any suitable way, either manually or by a foot treadle connected by a linkage 12 with the free end of the lever. The pulley 53 is secured to the shaft '62 and is driven thereby by engagement of the driving faces of the clutch.

The end plate 66 secured to the housing 55 by means of a series of screw-threaded studs 58 which engage both of the same, said studs carrying a series of nuts l t to retain the parts in proper assembled relation. Mounted on said studs is a support member l5 which may conveniently be of substantially horseshoe or C shape.

At opposite sides of the support member 15, preferably horizontally in line with the of the shaft 62, there are provided threaded apertures arranged to receive the threaded ends of a pair of wing-headed screws 15. These wingheaded screws are for the purpose of attaching to the support member 75 the housing of a blower unit to be described.

The blower housing comprises a main body member i"! in the volute-like form shown in Fig. 4. Attached to opposite sides of the member Tl there are suitable ears or lugs 78 apertured to receive the wing-headed screws '55. To the front face, or side which it will later be seen is not toward the motor, of the main body member ii, there is se cured, as by screws, a disc-like front cover plate 19, as shown in Fig. 4, conforming in outer contour with the contour of member Ti. As shown in Fig. 3, the back wall 30 of the blower housing may be formed as an integral part of member ii, or described in Patent 2,418,429 granted April 1, 1947 to George Sauer, may be a separate plate, similar to plate "i9, secured as by screws to member H. The blower housing is attached to the support member '55 by means of the wing-headed screws 16 and is spaced therefrom by means of a set of spacing collars 8!. Provision is made for protecting the lower part of the pulley and belt with a belt guard. This guard may be an integral extension of member Ti, or the spacing collars 85 may be formed with radially extending screw-threaded apertures, as of semi-cylindrical shape, secured to these collars by means of these apertures.

The central portion of the front and back walls of the blower housing is out out. The belt pulley 53 is provided with a hub extension, and a rotor or impeller 82 is mounted thereon within the blower housing. The hub fits fairly closely within the opening in the back wall of the blower housing. The opening in the front wall of the housing, or disc-like member 79, serves as the air inlet for the blower. The rotor 82 is provided with a plurality of generally radial vanes, the shape and configuration of the vanes and the design of the main body member T! being in accordance with accepted principles so as to provide an efli'cient blower construction.

The blower inlet is provided with an air filtering means, as shown in Figs. 4, 5, 6 and '7. As shown in Fig. 5, a cylindrical collar 83 is mounted on the member 19. concentric with the opening in same. A collar-like member 8 3 is provided which fits over collar 83. This member 84 is provided with an inner rim 85 toward one end, and a disc'like filter screen 86 or web of other filter material is inserted in said collar 85, being engaged between rirm 85 and collar 83 when collar 84 is fitted over 6. collar 83, as shown in Fig. 6. The collar 84 hearing the filter screen is shown in Fig. 7 in a perspective view. Air entering the blower will thus be filtered in the process, thereby preventing lint and other undesirable material from entering the air circulation system. The filter screen is readily removable and replaceable for cleaning purposes.

As shown in Figs. 1 and 3, the blower outlet is rectangular in form and is defined by extensions of the housing of the blower. As explained in the above-mentioned Sauer patent 2,418,429 granted April 1, 1947, various adjustments of the position of the blower may be made in order to provide for wear of the break and clutch surfaces. In order to provide for motion of the blower when these adjustments are made, the outlet of the blower is connected first with a flexible connection 81 of rubber, plastic, plastic-covered cloth, or the like, and this connection is then connected with a rigid conduit 88, of metal or other appropriate material. The housing i3 of the machine is provided with an input opening 89, and conduit 88 leads by means of a connection 98 to this opening for the delivery of a blast of air into the interior of the machine.

The housing, as stated, is generally enclosed, being provided with various small outlet openings such as St. During operation of the machine the blower provides a considerable flow of air into the housing and maintains a superatmospheric pressure within the housing. This pres sure will be great enough to cause a marked and continuous current of air to emerge from the various outlet openings of the machine. This serves to clean the interior of the machine, removing dust and lint therefrom, and the marked cur-- rent of air away from these openings on the exterior of the housing prevents such material from entering the housing.

The quantitative value of superatmospheric pressure maintained within the housing is related to the pressure-head-producing characteristics of the blower. Viewed differently, the superatmospheric pressure within the housing may .be considered related to the flow of air emerging from the outlet openings and the overall resistance of the outlet openings. The term flow of air, when used as a noun, will be considered to mean the quantity of air passing in a given time. The term resistance will be used to mean the ratio between pressure head and flow. In a quantitative analysis of conditions within the housing it may conveniently be assumed that a steady state is reached, and the flow of air into the housing is the same as that emerging therefrom.

Obviously the motor-driven air blower must be capable of maintaining a pressure head at least as great as the superatmospheric pressure desired within the housing. In the illustrated machine the superatmospheric pressure maintained within the housing may, for example, be equivalent to a head 0.05 inch of water. This pressure should be such as will maintain a substantially outward flow of air from the housing, and should in any event be equivalent to at least 0.01 inch of water.

The input opening 89 in the frame is located in such space relationship to the lubricated parts within the frame, and the configuration of conduit 88 and connection 90 are such that the blast of incoming air is directed against lubricated parts within the housing. Because of the airtransmitting capacity of the blower and the configuration of the conduit and connection, the

blast is of suflicient velocity to pick up excess oil which may be exposed on surfaces within the housing. Thus there is in the interior of the machine a region or zone of rather rapidly moving air, located near the input opening 89. This may be called a lubricant-picking-up zone. The housing may be considered to form an air conduit between the input opening and the outlet openings therein. Since a portion of the interior of the housing is filled with various moving and stationary members and a portion is void, it is the void portion which is thus effective as a conduit.

Assuming that air is incompressible, then its velocity of flow through a conduit of varying cross-sectional area will be inversely proportional to this cross-sectional area. In the present invention, the cross-sectional area of the input conduit 88 is less than the efiective or void cross sectional area of the housing in certain regions. There will thus be within the housing a zone wherein the velocity of the air "is lower than the velocity of the input blast or jet. In this lastmentioned zone, the lubricant carried by the air from the lubricant-picking-up zone may settle and be deposited upon various parts, thus aiding in the lubrication of the machine and preventing any appreciable quantity of lubricant from being borne from the outlet openings of the housing in the emerging air.

The outlet openings are each rather small, and air emerges from them with sufllciently high velocity to blow lint away from this zone. This could then be called a lint-blowing zone.

The air outlet openings are in general located 1 at points of the frame remote from the air input openings. The overall result of the space relationship of these openings and of the configuration of the housing is that instead of having only a small turbulent region of air near the air input openings, substantially all the air within the housing is kept in motion at a velocity of for example not less than, say, 40 feet per minute and the path of this motion is such as to carry the air efficiently out of the housing. Typical values for the air velocity in specific regions might be 4000 feet per minute in conduit 88, 4000 feet per minute in the lubricant-picking-up zone, 140 feet per minute in the lubricant-depositing zone, and 200 feet per minute in an air outlet opening of the housing. These values can be varied to a certain extent. For example, the velocity in the conduit 88 might be as low as 1000 feet per minute or as high as 6000 feet per minute, and the other velocities might vary accordingly.

The air which enters the blower is, as stated, filtered, and is drawn from a region a considerable distance from the machine, and for these reasons is quite clean and free from lint and dust. The passage of this large volume of air through the machine is of great help in keeping the interior of the machine cool, as the air picks up heat from the lubricant and moving parts and carries it from the machine.

Reference is made to Figs. 8 and 9. These figures show modified embodiments of the invention, featuring a motor 92 for the blower separate from the motor 55 which cooperates with the transmitter for driving the machine. One advantage of having a separate motor for the blower is the fact that the blower may then operate continuously, functioning between, as Well as during, seaming operations. This continuous operation is more effective in cooling the machine, and is also more effective in main- 8 taining the interior of the housing clean, inasmuch as lint or dust is prevented from settling within the housing during intervals between seaming operations. The motor 92 may be supported by a suitable supporting frame or plate 51a, which may be screwed to the table.

As shown in these figures, a more direct conduit 88a from the blower to the input opening of the housing is provided in this modification. The conduit is provided with a connection 89a to the housing. An important feature of this modification is the provision of means for direct ing a blast of air into the zone in which the needle operates. Thus in Figs. 8 and 9 the connection 89a is provided with a shoulder 93, and a tube 94 is pivotally mounted on said shoulder and adapted to conduct air to the needle-operating zone. A blast of air is thus directed against the needle for cooling and cleaning purposes. The pivotal mounting of the tube 94 enables the operator to swing the tube into such a position as to direct the blast of air away from the needle when desired, as when threading the needle.

While an illustrative form of the invention has been disclosed in considerable detail, it will be understood that various changes may be made in the construction and arrangement of the several par-ts without departing from the general principles and scope of the invention as defined by the appended claims.

I claim:

1. In a sewing machine having a work support and a needle and driving means therefor within a generally enclosed housing which extends partly above and partly below the work support, a cooling system comprising air input and outlet means comprising openings in said housing, said air input means being in the upper part of said housing, an air blower, a conduit connecting said blower to said input means for forcing air into the interior of said housing, means for filtering said air prior to its entry into said housing, and an air-conducting tube branching oif from said conduit exterior of said housing and leading to the zone of operation of said needle.

2. In a sewing machine comprising stitchforming means including a needle, a generally enclosed housing and means for operating said stitch-forming means including movable parts within said housing, a cooling and cleaning system, said system comprising air input and outlet means comprising openings in said housing, an air blower connected by a conduit to said input means for blowing into said housing a current of air having a flow of suflicient magnitude to produce a slight superatmospheric pressure within said housing, a circulation of air through said housing, and a rapid outward movement of air through said outlet means, a branch conduit leading from said first mentioned conduit exterior of said housing to the region in which said needle is operated for delivering a blast of air to said region, and an air filter connected in series with said blower in advance of said branch conduit.

3. In a sewing machine having a needle and a generally enclosed housing containing means for driving said needle, a cooling system comprising air input and outlet means comprising openings in said housing, an air blower external of said housing connected to said input means by a conduit for forcing a sufficient flow of air into the interior of said housing to maintain a slight superatmospheric pressure therein, said blower having an air intake means comprising an air intake opening, and a readily removable and replaceable filter, and a movable tube branching off from said conduit exterior of said housing adapted to direct a blast of air toward said needle, said tube being adapted to be moved to direct said blast of air away from said needle when said needle is to be threaded.

4. A cooling system for a sewing machine having a needle, a first motor for operating same, and a generally enclosed housing, said system comprising a blower driven by a second motor, a conduit for conducting air from said blower into the interior of said housing, a tube branching off from said conduit and pivotally connected to same leading to the zone in which said needle operates, said frame being provided with an air outlet opening, said blower being provided with an air intake opening and an air intake filter, said filter comprising a web of filter material, a rimmed frame for holding said web, and means for attaching said frame to said blower across the air intake opening of said blower.

5. A system for cooling, lubricating, and cleaning a sewing machine of the type having a work surface lying in a generally horizontal plane, a needle adapted to pass downwardly through said work surface, a frame having a hollow base portion below the plane of said work surface and a hollow upper portion above said plane forming a generally enclosed housing, communicating therewith, needle actuating means within said upper portion including a substantially horizontal drive shaft extending therethrough, stitch-forming means cooperating with said needle within said lower portion, and connections from said shaft to said stitch-forming means for actuating the latter, said system comprising an oil reservoir above said shaft, oil conduit means for conducting oil from said reservoir to said needle actuating means, said frame having an air inlet opening approximately at the elevation of said shaft and air outlet means below the plane of said work surface, a blower, and an air conduit leading from said blower to said air inlet opening, whereby a jet of air is directed by said air conduit against lubricated surfaces of said needle-actuating means and is caused to pick up oil therefrom and carry the same through said housing, said oil being deposited in other regions thereof, including regions below said work surface.

6. A system for cooling, lubricating and cleaning a sewing machine of the type having a generally horizontal work surface, a needle, a frame having hollow intercommunicating upper and lower portions above and below said work surface respectively, actuating means within said upper portion, and stitch-forming means within said lower portion, said system comprising, in combination, a blower, an oil reservoir near the top of said upper portion, oil conduit means for conducting oil from said reservoir to said actuating 10 means for directly lubricating same, air inlet means connected to said blower comprising an opening in the side of said frame opposite said directly lubricated actuating means, air outlet means comprising an opening in said frame below said work surface, said frame having void regions, including regions surrounding said stitchforming means, forming a conduit between said air inlet and said air outlet means having an effective cross sectional area larger than the cross sectional area of said air inlet means, whereby a jet of air is directed by said air inlet means against directly lubricated surfaces in the upper portion of said frame and is caused to pick up lubricant therefrom and to deposit the same in other regions of said frame.

'7. A system for cooling, lubricating, and cleaning a sewing machine of the type having a generally horizontal work surface, a needle, a generally enclosed frame having hollow intercommunicating upper and lower portions above and below said work surface, respectively, actuating means within said upper portion, stitch-forming means within said lower portion, said system comprising, in combination, an oil reservoir near the top of said upper portion, oil conduit means for conducting oil from said reservoir to said actuating means for directly lubricating same, air inlet means comprising an opening in said frame intermediate the top thereof and said work surface, opposite said directly lubricated actuating means, a blower connected to said air inlet means, air outlet means comprising openings in said frame below said work surface, the total crosssectional area of said air outlet openings being related to the air transmitting capacity of said blower so that a slight superatmospheric pressure is maintained within said housing to cause an outward flow of air from all outlet openings of said housing, the arrangement being such that a jet of air is directed by said air inlet means against directly lubricated surfaces of said actuating means in said upper portion of said frame and is caused to pick up lubricant and carry the same through said housing, said lubricant being deposited on bearing surfaces of said stitch-forming means in said lower portion of said frame.

NORMAN V. CHRISTENSEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,326,886 Wineman Dec. 30, 1919 1,333,594 Allen Mar. 16, 1920 1,719,255 Woodford -o July 2, 1929 2,082,738 Vesconte June 1, 1937 2,180,756 Harding Nov. 21, 1939 2,400,741 Christensen et a1. May 21, 1946 

